Database Redo Log Optimization Skipping MVCC Records
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Solution Overview
Problem
Database recovery processes are time-consuming due to the need to replay extensive transaction logs, including both data log records and multi-version concurrency control (MVCC) log records, leading to prolonged downtime during system restoration.
Innovation Solution
The solution involves skipping MVCC redo log records during the database recovery process, specifically omitting insert and update MVCC log records while replaying data log records based on the most recent savepoint, thereby reducing the recovery time by leveraging the information already present in the data log records.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MVCC redo log records are replayed during database recovery, then data consistency is ensured, but recovery time is prolonged
Solution Approach 1:
The patent extracts and removes MVCC log records from the replay process during database recovery. By identifying that MVCC records are redundant when data log records are already being replayed, the system selectively excludes MVCC records from the recovery operation, thereby reducing recovery time while preserving data consistency through the remaining data log records
Solution Approach 2:
The patent applies the principle of discarding unnecessary MVCC log records during recovery while still achieving the desired recovery outcome. The system selectively discards MVCC records that would be redundant given the presence of data log records, allowing faster recovery without compromising data integrity
2Reliability
If extensive transaction logs including MVCC log records are replayed, then complete transaction history is restored, but database downtime is prolonged
Solution Approach 1:
The patent extracts only the essential data log records needed for recovery, excluding MVCC log records from the replay process. This selective extraction maintains complete transaction history restoration through data log records while significantly reducing the time required, thereby improving database availability during recovery operations
3Reliability
If all redo log records are replayed during recovery, then data integrity is maintained, but recovery speed is reduced
Solution Approach 1:
The patent implements skipping of MVCC log records during the recovery process. By recognizing that data log records already contain the necessary information for data integrity, the system rushes through the recovery by omitting redundant MVCC records, thereby maintaining data integrity while significantly accelerating recovery speed
Data Source
AI summary
Restoring of a database table in the database system (e.g., an in-memory insert-only database system, etc.) is initiated. Thereafter, a transaction log volume storing data log records and multi-version concurrency control (MVCC) log records corresponding to the database table is accessed. Based on such access, data log records corresponding to the database table are replayed while insert and update MVCC log records corresponding to the database table are skipped. Subsequently, restoring of the database table in the database system is finalized. Related apparatus, systems, techniques and articles are also described.